The availability of polyethylene and other polymers derived from polymerization of olefins have revolutionized modem society. Such materials are responsible for innovations, which touch and concern nearly every aspect of modem day life. Polymerization catalysts used in obtaining these materials thus offer opportunities for providing new processes and products to the markets. In particular, supported olefin polymerization catalyst systems are of great interest in making polymeric products available.
Metal containing catalysts may be used in producing polyolefins from alpha-olefins such as ethylene. Polyolefins may be produced by contacting olefins under polymerization conditions with “Ziegler” type catalyst, which may have a Group 4 or 5 transition metal component. A co-catalyst may also be present; see for example U.S. Pat. Nos. 4,224,185, 4,220,555, 4,143,223, 3,623,846, and British Pat. No. 1,139,450 directed to a co-catalyst comprising titanium, which may be activated with an organometallic compound.
Chromium compounds and complexes may also be used as catalysts for the polymerization of olefins. U.S. Pat. Nos. 3,324,095, 3,324,101, 3,642,749, and 3,704,287 are directed to a catalyst, which includes silyl chromate and polyalicyclic chromate esters. U.S. Pat. Nos. 3,704,287, 3,474,080, and 3,985,676 are directed to phosphorus-containing chromate esters which may also be used in olefin polymerization catalysts. U.S. Pat. No. 4,359,562 is directed to a process of ethylene polymerization using a supported chromium-hydrocarbon complex, and WO2000/61645 is directed to a polymerization catalyst that includes chromium in combination with an organoaluminum material, and an organomagnesium material.
Other chromium catalysts may include: U.S. Pat. Nos. 3,324,101, 3,642,749, 3,704,287, 3,806,500, and 4,467,080, which are directed to chromium compound catalysts in coordination catalyst systems; U.S. Pat. No. 6,300,272 directed to chromium catalyst on a silica support; U.S. Pat. No. 6,245,869 directed to a chromium-based catalyst having a silica and titania support along with a co-catalyst of an aluminum or zinc alkyl; and U.S. Pat. No. 6,096,679 directed to a chromium-based catalyst for the production of polyethylene using a catalyst support of silica, silica-titania, or silica-zirconia.
Catalysts may also be associated with a support. See for example U.S. Pat. Nos. 2,852,721 and 2,951,816, directed to the use of CrO3 supported on an inorganic material that may include silica, alumina or combinations of silica and alumina, and which may be activated by heating in a reducing atmosphere. Combinations of different catalysts on a support may also be used to produce polyolefins, examples include: U.S. Pat. No. 3,882,096 directed to a catalyst and method of preparing ultra high molecular weight polyolefins using chromium oxide on a support in combination with an alkyl ester of titanium; U.S. Pat. No. 3,622,522 directed to an alkoxide of gallium or tin added to supported chromium oxide prior to heat activation; U.S. Pat. No. 3,715,321 directed to adding a compound of a Group 2 or Group 3 metal to supported chromium oxide prior to heat treatment; U.S. Pat. No. 3,780,011 directed to adding alkyl esters of titanium, vanadium or boron; U.S. Pat. No. 3,484,428 directed to adding alkyl boranes to a supported catalyst; and U.S. Pat. No. 5,189,000 directed to using organometallic compound of aluminum with a titanium, vanadium, or chromium catalyst.
Aluminosilicates and other siliceous materials may be used as supports for olefin polymerization catalysts. U.S. Pat. Nos. 5,057,296 and 5,200,058 are directed to a catalyst comprising an active form of a functionalized inorganic, porous, non-layered crystalline phase having uniformly sized pores of at least about 13 Å, and a Group 6 metal. U.S. Pat. Nos. 5,105,051 and 5,270,273 are directed to oligomerizing alpha olefins to produce hydrocarbon oligomers useful as lubricants and lubricant additives using a catalyst comprising a supported reduced Group 6 metal, preferably chromium, in the form of its oxide on a mesoporous, inorganic, crystalline solid having a specific pore geometry described as a uniform hexagonal honeycomb microstructure, with uniform pores having a cell diameter greater than 13 Å. International Application WO2002/40551, and EP 827,969 A2 are directed to using mesoporous supports having pore diameters of from 2 to 10 nanometers.
An olefin polymerization process may comprise contacting a catalyst with the olefin at constant temperature and pressure. Upon this contact however, a lag time referred to herein as an induction time may then ensue prior to an appreciable commencement of the polymerization process. This induction time may be monitored by the consumption of the olefin feed stock flowing into the constant pressure reactor. Accordingly, it is beneficial to utilize a catalyst system, which provides a polymer having the desired properties, at the desired rate of conversion, which also provides for a relatively low induction time. However, chromium based catalysts systems may be characterized as having relatively long induction times with relatively low rates of conversion. Accordingly, there remains a need for supported chromium based catalysts having relatively short induction times that provide for relatively high catalytic activities under polymerization conditions, and which produce polymers having desired attributes which may include a particular bulk density, molecular weight distribution, and/or the like.
Other References of Interest Include:    1. U.S. Pat. No. 5,220,101; Sorption separation over modified synthetic mesoporous crystalline material    2. U.S. Pat. No. 5,171,915; Alkylaromatic lubricants from alpha-olefin dimer    3. U.S. Pat. No. 5,146,021; Enhancing compositions and Newtonian lube blends    4. U.S. Pat. No. 5,145,816; Method for functionalizing synthetic mesoporous crystalline material    5. U.S. Pat. No. 5,132,477; Process for producing alkylaromatic lubricant fluids    6. U.S. Pat. No. 5,105,051; Production of olefin oligomer lubricants    7. U.S. Pat. No. 5,105,039; Process for producing lubricant fluids of improved stability    8. U.S. Pat. No. 5,087,782; Dehydrocyclization of polyalpha-olefin lubricants    9. U.S. Pat. No. 5,019,670; Process for producing alkylaromatic lubricant fluids    10. U.S. Pat. No. 5,015,795; Novel synthetic lube composition and process    11. U.S. Pat. No. 4,996,384; Regeneration of reduced metal oxide oligomerization catalyst    12. U.S. Pat. No. 4,990,718; Aromatic alkylation with alpha-olefin dimer    13. U.S. Pat. No. 4,967,030; Hydrocracking high viscosity synthetic lubricant    14. U.S. Pat. No. 4,926,004; Regeneration of reduced supported chromium oxide catalyst for alpha-olefin oligomerization    15. U.S. Pat. No. 4,914,254; Fixed bed process for high viscosity index lubricant    16. U.S. Pat. No. 4,711,710; Process for making improved lubricating oils from heavy feedstock